Snap-action operating system in an electric switch



Sept. 26, 1967 SHlGEO MAMIYA 3,344,246

SNAP-ACTION OPERATING SYSTEM IN AN ELECTRIC SWITCH Filed March 18, 19665 Sheets-Sheet 1 INVENTOR. SHIGEO MHMW BY WW Se t. 26, 1967 SHIGEOMAMIYA SNAP-ACTION OPERATING SYSTEM IN AN ELECTRIC SWITCH 5 Sheets-Sheet2 Filed March 18, 1966 fig. 4

INVENTOR. SH/GEO MHMNH BY WM W W Se t. 26, 1967 SHIGEO MAMIYASNAP-ACTION OPERATING SYSTEM IN AN ELECTRIC SWITCH 5 Sheets-$heet 3Filed March 18, 1966 INVENTOR. SH/GEO HEMP/H BY MM 6% P 26, 1967 SHIGEOMAMIYA 3,344,246

SNAP-ACTION OPERATING SYSTEM IN AN ELECTRIC SWITCH Filed March 18, 19665 Sheets -Sheet 4 Fig. 11

(Contact ressure) INVENTOR. SHIGEO MAM/YR p 1967 SHIGEO MAMIYA 3,344,246

SNAP-ACTION OPERATING SYSTEM IN AN ELECTRIC SWITCH Filed March 18, 19665 Sheets-Sheet 5 INVENTOR. SH/GEO I IHMIYH United States Patent OfiicePatented Sept. 26, 1967 3,344,346 SNAP-AtITION OPERATING SYSTEM EN ANELECTR SWITCH Shigeo Mamiya, Tokyo, Japan, assignor to Kahushiiai-Keisha Saginomiya Seisairusho, Tokyo, Eapan Filed Mar. L3, 1966, Ser.No. 535,499 3 Claims. (Cl. 2D0-67) This invention relates to asnap-action operating system in an electric switch.

An object of the present invention is to provide a novel snap-actionoperating system in an electric switch wherein a movable contact platehaving a movable contact thereon may have a predetermined contactpressure applied thereto notwithstanding fluctuations in contactpressure due to the make and break operations of the switch, so that adecrease in contact pressure acting on the movable contact, andconsequently chattering between the movable contact and the fixedcontacts may be prevented, and wherein the reversible movement of themovable contact between the fixed contacts may be rapid and smooth.

As a rule, when the movable contact plate, having its movable contact intouch with one of the fixed contacts disposed in spaced parallelrelation, is to be reversed by the pressure acting thereon to makecontact with the other fixed contact, the movable contact has to bereversed quickly from one to the other of the fixed contacts, and thereversing force of the movable contact plate, that is, the contactpressure applied to the movable contact, has to be maintained at apredetermined value notwithstanding fluctuations in contact pressureresulting from the maize and break operations of the switch. However, anelectric switch of the ordinary type, especially a switch using the snapaction of the spring for reversibl operation of the movable contact, hasthe disadvantage that the pressure acting on the movable contact platewill ecrease while the latter is reversibly operated, and this resultsin a so-called chattering between the movable contact and the fixedcontact due to the oscillations of the movable contact, especially wherethe decrease in the pressure acting on the movable contact plate isconsiderable.

The snap-action operating system in an electric switch according to thepresent invention comprises at least one movable contact plate having atleast one movable contact thereon and provided with a gap or aperture atone end and a quick-reverse spring at the other end; at least one pairof fixed contacts disposed in opposition and facing toward oppositesides of said movable contact; a first operating plate having a buttonto press the same and a Ushaped leaf sprin carried at one end by it andat the other end by a second operating plate; said second operatingplate extending, near its end carried by the U-shaped spring through thegap formed at the one end of the movable contact plate.

In the drawings:

FIGS. 1 to 8 are explanatory side elevational views showing thestructure of an embodiment of the snapaction electric switch inaccordance with the present invention, with the parts thereof insuccessive operative states;

FIG. 9 is an explanatory side elevational view showing the pressureapplied to each part of the switch in the position indicated in FIG. 1;

FIG. 10 is an explanatory side elevational view similar to FIG. 9 andshowing the pressure applied to each member of the switch in theposition indicated in FIG. 5;

FIG. 11 is a graph showing the pressure applied to the movable contactof the switch While the movable contact is reversibly operated;

FIGS. 12 and 13 are explanatory perspective views showing twoalternative constructions of the movable contact plate of the switch;

FIG. 14 is an explanatory perspective view showing, in concrete form, anembodiment of the operating plate of the switch having a U-shaped leafspring; and

FIGS. 15 and 16 are explanatory side elevational views showing otherembodiments of the snap-action electric switch according to the presentinvention.

Referring to the accompanying drawings, by way of explaining in moredetail some of the embodiments of the present invention illustratedtherein, 1 in each figure is a movable operating plate on finger securedat one end and 2 is a U-shaped leaf spring carried by the free end ofoperating plate 1. The U-shaped leaf spring 2 is interposed between saidoperating plate 1 and a second rocka'ole operating plate on finger 3pivoted at one end, and is held at p and q by the free ends of theoperating plate 1 and of the second operating plate 3, respectively. 4is a button for pressing the operating plate 1, and 5 is a reversiblecontact plate or finger having a quick-reverse spring 6. Fixed contacts8, 9 are disposed above and beneath the movable contact 7 in alignmentwith the latter and with each other. A gap G is provided on the bentportion 10 of the snap-action contact plate 5, and the second operatingplate 3, operatively connected with the operating plate 1 by theU-shaped leaf spring 2, is inserted rockably through gap G.

Based on the structure of the snap-action operating system in anelectric switch as above noted, the operation thereof will now bedescribed with reference to FIGS. 1 to 11. The button 4 as indicated inFIG. 1 is operated in the first place in a direction to press theoperating plate 1, which reaches the operative state as indicated inFIG. 5 by passing through the states of FIGS. 2, 3 and 4. At this time,the movable contact 7 of the reversible contact plate 5 engages thefixed contact 9 on the side opposite to the fixed contact 8. Conversely,if the pressure on the button 4 is released from the state as shown inFIG. 5, the movable contact 7 is reversed and reaches the state asindicated in FIG. 1 by passing through the states of FIGS. 6, 7 and 8.

With the operating plate 1 in a state as shown in FIG. 1, the secondoperating plate 3 is urged into contact with the reversible contactplate 5 by the U-shaped leaf spring 2 with compressing force Pa and bythe tension of the quick-reverse spring 6 of the reversible contactplate 5 with compressing force fa as shown in FIG. 9. In efiect, thecontact pressure applied to the fixed contact 8 by the movable contact 7is given by f'(f )+f"( in which 1" and f" are constants.

If the button 4 is pressed at this state, the U-shaped leaf spring 2starts to be deformed gradually and the second operating plate 3 ismoved in a direction as indicated by the arrow mark to the right of gapG. The second operating plate 3, while it is reversed quickly throughthe states of FIGS. 2 and 3, engages with the marginal edge of the gap Gin the state of FIG. 4, and rotates the reversible contact plate 5quickly. Thus the movable contact 7 is disengaged from fixed contact 7and is reversed with a quick snap action, assuming the state as shown inFIG. 5. At this instant, the quick-reverse sprin also recoils quicklyand the movable contact is pressed with a predetermined contact pressureto mak contact with the fixed contact 9. With the switch in the state ofFIG. 5, the contact pressure acting on the fixed contact 9 will beconsidered with reference to FIG. 10. If the pressure applied to thesecond operating plate 3 by the U-shaped leaf spring 2 of the operatingplate l is Pb and the pressure applied to the second operating plate 3by the quick-reverse spring 6 is fb, then the contact pressure acting onthe fixed contact 9 is given by in which 7" and f are constants.

If new the pressure applied to the button 4 is released from the stateof FIG. 5, the second operating plate 3, engaging the one marginal edgeof the gap G, moves the operating plate 1 by degrees in a directionshown by the arrow mark in FIG. 6, due to the deformation of theU-shaped leaf spring 2, and reaches the operative state as shown in FIG.7 by passing through the state of FIG. 6. At this instant, thecompressing force applied by the U-shaped leaf spring 2 is reduced toZero, and only the reversible contact plate is applying pressure to thesecond operating plate 3. When the switch device reaches the state asshown in FIG. .8, the second operating plate 3, engaging at this timewith the opposite marginal edge of the gap G, presses the reversiblecontact plate 5 in the opposite direction until the operative stateindicated in FIG. 1 is assumed a second time.

Thus, it will be appreciated that the reversible operation of themovable contact by the pressing and release of the button 4 is theso-called reversible kicking system and that, as shown in FIG. 11, thecontact pressure applied to the fixed contact is never reduced to zeroregardless of the positions assumed by the button 4 while the latter isin operation, the contact pressure acting on the movable contactremaining substantially above f'(fa) or f"'(f It is to be noted that thepresent invention includes a modified structure in which the twosnap-action operating systems each having a U-shaped leaf spring of thetype as above described are stacked or connected in parallel as shown inFIGS. and 16. These embodiments use the component constructions shown inFIGS. 13, 14 and 15.

As noted in the foregoing, the present invention provides a snap-actionoperating system embodying the socalled discontinuous contact pressuresystem in which the contact pressure may be maintained in excess of apredetermined value while the contact means are reversibly operated. Themake and break operation of the electric switch may be done rapidly andsmoothly, and the snap-action operating system of the present inventionenables the switch system to be controlled or adjusted smoothly andpositively if it is utilized in a switch system for automatic regulationor adjustment of electric apparatuses.

What is claimed is:

1. A snap action electric switch comprising, in combination, at leastone quickly reversible contact member in the form of a relativelyelongated first plate of resilient material fixedly mounted at one fixedend and having an opposite free end, said free end having a flange bentsubstantially at right angles to the general plane of said plate andformed with a substantially rectangular first aperture therethroughhaving first and second substantially parallel edges substantiallyparallel to the general plane of said plate; at least one movablecontact carried by said contact member adjacent its free end; saidcontact member having a second aperture intermediate its ends, having anedge remote from said fixed end extending transversely of said firstplate; a quickreverse spring having a fixed end engaging an abutmentadjacent said fixed end of said first plate and a free end 0 endadjacent the fixed end of said contact member and having an oppositefree end, said operating member including a portion extending throughsaid first aperture of said contact member and being formed with a thirdaperture which is substantially rectangular and has opposite end edgesextending substantially parallel to said flange; a first tongueextending from one end edge of said third aperture and a second tongueextending from the other end edge of said third aperture toward saidfirst tongue, the adjacent ends of said first and second tongues beingspaced longitudinally from each other; said first tongue constitutingsaid operating member portion extending through said first aperture ofsaid contact member, and the adjacent ends of both tongues beingoutwardly of said flange; a U-shaped leaf spring having the end portionof each leg engaged with the end of a respective tongue, said U-shapedleaf spring being compressed between the adjacent ends of said tongue;an operating button engaged with said operating member adjacent its freeend beyond said third aperture; the distance between said first andsecond substantially parallel edges of said first aperture beingsubstantially less than the range of movement of said first tongueextending through first aperture; said U-shape leaf spring beingrockable about the adjacent free ends of said first and second tonguesand rocking about said adjacent free ends responsive to movement of saidsecond tongue in either direction to effect a snap displacement of saidfirst tongue into engagement with a respective one of said first andsecond substantially parallel edges of said first aperture to snap saidcontact member in a respective direction to disengage said movablecontact from one of said fixed contacts and snap said movable contactinto engagement with the other of said fixed contacts.

2. A snap action electric switch, as claimed in claim 1, in which saidabutment comprises a second edge of said second aperture substantiallyparallel to said firstmentioned edge and closely adjacent the fixed endof said contact member.

3. A snap action electric switch, as claimed in claim 2, in which saidabutment comprises a fixed abutment extending through said secondaperture of said contact member immediately adjacent the fixed end ofsaid contact member.

References Cited UNITED STATES PATENTS 2,487,374 11/1949 Riche et al20067 2,515,528 7/1950 Rothwell 20067 2,574,429 11/ 1951 Wood 200672,581,705 1/1952 Riche 20067 3,226,511 12/ 1965 Mertler 2001382 ROBERTK. SCHAEFER, Primary Examiner.

D. SMITH, In, Assistant Examiner.

1. A SNAP ACTION ELECTRIC SWITCH COMPRISING, IN COMBINATION, AT LEASTONE QUICKLY REVERSIBLE CONTACT MEMBER IN THE FORM OF A RELATIVELYELONGATED FIRST PLATE OF RESILIENT MATERIAL FIXEDLY MOUNTED AT ONE FIXEDEND AND HAVING AN OPPOSITE FREE END, SAID FREE END HAVING A FLANGE BENTSUBSTANTIALLY AT RIGHT ANGLES TO THE GENERAL PLANE OF SAID PLATE ANDFORMED WITH A SUBSTANTIALLY RECTANGULAR FIRST APERTURE THERETHROUGHHAVING FIRST AND SECOND SUBSTANTIALLY PARALLEL EDGES SUBSTANTIALLYPARALLEL TO THE GENERAL PLANE OF SAID PLATE; AT LEAST ONE MOVABLECONTACT CARRIED BY SAID CONTACT MEMBER ADJACENT ITS FREE END; SAIDCONTACT MEMBER HAVING A SECOND APERTURE INTERMEDIATE ITS ENDS, HAVING ANEDGE REMOTE FROM SAID FIXED END EXTENDING TRANSVERSELY OF SAID FIRSTPLATE; A QUICKREVERSE SPRING HAVING A FIXED END ENGAGING AN ABUTMENTADJACENT SAID FIXED END OF SAID FIRST PLATE AND A FREE END ENGAGED WITHSAID EDGE OF SAID SECOND APERTURE, WHEREBY SAID QUICK-REVERSE SPRING ISCOMPRESSED BETWEEN SAID ABUTMENT AND SAID LAST-NAMED EDGE AND OPERABLETO SNAP THE FREE END OF SAID CONTACT MEMBER IN OPPOSED RESPECTIVEDIRCTIONS AFTER A PREDETERMINED INITIAL MOVEMENT OF SAID CONTACT MEMBERIN A RESPECTIVE DIRECTION; A PAIR OF SPACED FIXED CONTACTS ALIGNED WITHEACH MOVABLE CONTACT AND FACING RESPECTIVE OPPOSITE SIDES OF THE LATTER;AN OPERATING MEMBER IN THE FORM OF A RELATIVELY ELONGATED SECOND PLATEOF RESILIENT MATERIAL FIXEDLY MOUNTED AT ONE FIXED END ADJACENT THEFIXED END OF SAID CONTACT MEMBER AND HAVING AN OPPOSITE FREE END, SAIDOPERATING MEMBER INCLUDING A PORTION EXTENDING THROUGH SAID FIRSTAPERTURE OF SAID CONTACT MEMBER AND BEING FORMED WITH A THIRD APERTUREWHICH IS SUBSTANTIALLY REECTANGULAR AND HAS OPPOSITE END EDGES EXTENDINGSUBSTANTIALLY PARALLEL TO SAID FLANGE; A FIRST TONGUE EXTENDING FROM ONEEND EDGE OF SAID THIRD APERTURE AND A SECOND TONGUE EXTENDING FROM THEOTHER END EDGE OF SAID THIRD APERTURE TOWARD SAID FIRST TONGUE, THEADJACENT ENDS OF SAID FIRST AND SECOND TONGUES BEING SPACEDLONGITUDINALLY FROM EACH OTHER; SAID FIRST TONGUE CONSTITUTING SAIDOPERATING MEMBER PORTION EXTENDING THROUGH SAID FIRST APERTURE OF SAIDCONTACT MEMBER, AND THE ADJACENT ENDS OF BOTH TONGUES BEING OUTWARDLY OFSAID FLANGE; A U-SHAPED LEAF SPRING HAVING THE END PORTION OF EACH LEGENGAGED WITH THE END OF A RESPECTIVE TONGUE, SAID U-SHAPED LEAF SPRINGBEING COMPRESSED BETWEEN THE ADJACENT ENDS OF SAID TONGUE; AN OPERATINGBUTTON ENGAGED WITH SAID OPERATING MEMBER ADJACENT ITS FREE END BEYONDSAID THIRD APERTURE; THE DISTANCE BETWEEN SAID FIRST AND SECONDSUBSTANTIALLY PARALLEL EDGES OF SAID FIRST APERTURE BEING SUBSTANTIALLYLESS THAN THE RANGE OF MOVEMENT OF SAID FIRST TONGUE EXTENDING THROUGHFIRST APERTURE; SAID U-SHAPE LEAF SPRING BEING ROCKABLE ABOUT THEADJACENT FREE ENDS OF SAID FIRST AND SECOND TONGUES AND ROCKING ABOUTSAID ADJACENT FREE ENDS RESPONSIVE TO MOVEMENT OF SAID SECOND TONGUE INEITHER DIRECTION TO EFFECT A SNAP DISPLACEMENT OF SAID FIRST TONGUE INTOENGAGEMENT WITH A RESPECTIVE ONE OF SAID FIRST AND SECOND SUBSTANTIALLYPARALLEL EDGES OF SAID FIRST APERTURE TO SNAP SAID CONTACT MEMBER IN ARESPECTIVE DIRECTION TO DISENGAGE SAID MOVABLE CONTACT FROM ONE OF SAIDFIXED CONTACTS AND SNAP SAID MOVABLE CONTACT INTO ENGAGEMENT WITH THEOTHER OF SAID FIXED CONTACTS.